eSIM vs Your Carrier's International Roaming Plan
Your home carrier offers international roaming. Is it cheaper and easier than a travel eSIM? For most travelers the answer is no — here is why, with real numbers.
What carriers charge for international roaming
Most carriers offer international day passes: you pay a flat fee per day to use your home plan abroad. Common pricing (2025–2026):
- **AT&T International Day Pass:** ₩15,840/day
- **Verizon TravelPass:** ₩13,200/day
- **T-Mobile:** free roaming on 215 countries (capped at 128kbps — unusable for navigation)
- **EE (UK) Roam Anywhere:** £2/day in selected countries
- **Vodafone (UK) Roaming:** £3–£6/day
For a 7-day trip, that's ₩92,400–₩110,880 in US carrier day pass fees — for the same data you could get on a travel eSIM for ₩13,200–₩33,000
When your carrier roaming plan is worth it
When a travel eSIM is significantly cheaper
The hidden T-Mobile "free roaming" trap
T-Mobile advertises free international roaming as a flagship feature. What it actually provides at no extra cost: 128kbps data (equivalent to 2G dial-up — slow enough that Google Maps takes 30+ seconds to load a single tile). For video calls, navigation, or any real use, T-Mobile's free roaming is unusable. Their "High Speed Data" add-ons range from ₩6,600–₩19,800/day — comparable to or more expensive than a travel eSIM.